Eject All Disks:

This ejects everything except your boot disk, and a disk called “Media”, in my example. Feel free to build your own exception list by just modifying and adding on to the otherDisks definition.

tell application "Finder"
	set bootDisk to name of startup disk
	set otherDisks to every disk whose (name is not bootDisk) and (name is not "Media")
	repeat with myDisk in otherDisks
		try
			eject myDisk
		end try
	end repeat
end tell

Eject Server Volumes:

tell application "Finder" to eject (every disk whose local volume is false)